Went very smoothly.

As in previous installs, it was necessary to restore some manual configurations, viz:

Note that zmbackup commands in crontab that contain options which aren't compatible with zmschedulebackup are simply deleted on upgrade. So I find it easiest to do zmschedulebackup -D to insert the default backup schedule, then I modify it. There are some bugzilla entries (41332, 45634, 50584, 54702, 54709) related to this issue, which will be fixed in Helix.